KEUPER  , in

geology the third or uppermost subdivision of the Triassic system . The name is a local miners' term of German origin; it corresponds to the French marnes irisees . The formation is well exposed in Swabia, Franconia, Alsace and Lorraine and Luxemburg; it extends from Basel on the east side of the Rhine into Hanover, and northwards it spreads into Sweden and through England into Scotland and north-east Ireland; it appears flanking the central plateau of France and in the Pyrenees and Sardinia . In the German region it is usual to divide the Keuper into three groups, the Rhaetic or upper Keuper, the middle, Hauptkeuper or gypskeuper, and the lower, Kohlenkeuper or Lettenkohle . In Germany the lower division consists mainly of grey clays and schieferletten with white, grey and brightly coloured sandstone and dolomitic limestone . The upper part of this division is often a grey dolomite known as the Grenz dolomite; the impure coal beds—Lettenkohle—are aggregated towards the base . The middle division is thicker than either of the others (at Gottingen, 450 metres); it consists of a marly series below, grey, red and green marls with gypsum and dolomite—this is the gypskeuper in its restricted sense . The higher part of the series is sandy, hence called the Steinmergel; it is comparatively free from gypsum . To this division belong the Myophoria beds (M . Raibliana) with galena in places; the Estheria beds (E. laxitesta); the Schelfsandstein, used as a building-stone; the Lehrberg and Berg-gyps beds; Semionotus beds (S . Bergeri) with building-stone of Coburg; and the Burg-and Stubensandstein . The salt,which is associated with gypsum, is exploited in south Germany at Dreuze, Pettoncourt, Vie in Lorraine and Wimpfen on the Neckar .

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metre coal is found on this horizon in the Erzgebirge, and another, 2 metres thick, has been mined in Upper Silesia . The upper Keuper, Rhaetic or Avicula contorta zone in Germany is mainly sandy with dark grey shales and marls; it is seldom more than 25 metres thick . The sandstones are used for building purposes at Bayreuth, Culmbach and Bamberg . In Swabia and the Wesergebirge are several " bone-beds," thicker than those in the middle Keuper, which contain a rich assemblage of fossil remains of fish, reptiles and the mammalian teeth of Microlestes antiquus and Triglyptus Fraasi . The name Rhaetic is derived from the Rhaetic Alps where the beds are well developed; they occur also in central France, the Pyrenees and England . In S.Tirol and the Judicarian Mountains the Rhaetic is represented by the Kossener beds . In the Alpine region the presence of coral beds gives rise to the so-called " Lithodendron Kalk." In Great Britain the Keuper contains the following sub-divisions: Rhaetic or Penarth beds, grey, red and green marls, black shales and so-called " white lias " (10-150 ft.) . Upper Keuper marl, red and grey marls and shales with gypsum and 1 Miller's Artillery Regimental History; see also H . G . Farmer, op . Cit., p . 22 ; illustration 1702, p .

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Memoirs of tki Royal Artillery.rock salt (800-3oo ft.) . Lower Keuper sandstone, marls and thin sandstones at the top, red and white sandstones (including the so-called " waterstones ") below, with breccias and conglomerates at the base (150-250 ft.) . The basal or " dolomitic conglomerate " is a shore or scree breccia derived from local materials; it is well developed in the Mendip district . The rock-salt beds vary from 1 in. to Too ft. in thickness; they are extensively worked (mined and pumped) in Cheshire, Middlesbrough and Antrim . The Keuper covers a large area in the midlands and around the flanks of the Pennine range; it reaches southward to the Devonshire coast, eastward into Yorkshire and north-westward into north Ireland and south Scotland . As in Germany, there are one or more " bone beds " in the English Rhaetic with a similar assemblage of fossils . In the " white lias " the upper hard limestone is known as the " sun bed " or " Jew stone "; at the base is the Cotham or landscape marble . Representatives of the Rhaetic are found in south Sweden, where the lower portion contains workable coals, in the Himalayas, Japan, Tibet, Burma, eastern Siberia and in Spitzbergen . The upper portion of the Karroo beds of South Africa and part of the Otapiri series of New Zealand are probably of Rhaetic age . The Keuper is not rich in fossils; the principal plants are cypress-like conifers (Walchia, Voltzia) and a few calamites with such forms as Equisetum arenaceum and Pterophyllum Jaegeri, Avicula contorta, Protocardium rhaeticum, Terebratula gregaria, Myophoria costata, M . Goldfassi and Lingula tenuessima, Anoplophoria lettica may be mentioned among the invertebrates .

Fishes include Ceratodus, Hybodus and Lepidotus . Labyrinthodonts represented by the footprints of Cheirotherium and the bones of Labyrinthodon, Mastodonsaurus and Capitosaurus . Among the reptiles are Hyperodapedon, Palaeosaurus, Zanclodon, Nothosaurus and Belodon . Microlestes, the earliest known mammalian genus, has already been mentioned . See also the

article TRIASSIC SYSTEM . (J . A .